package com.yf.idmt.utils;

import javax.servlet.http.HttpServletRequest;
import java.net.InetAddress;
import java.net.UnknownHostException;

/**
 * 获取IP方法
 *
 * @author tanghailan
 */
public class IpUtils {
  public static String getIpAddr(HttpServletRequest request) {
    String ip = null;

    // X-Forwarded-For：Squid 服务代理
    String ipAddresses = request.getHeader("X-Forwarded-For");
    if (ipAddresses == null
        || ipAddresses.length() == 0
        || "unknown".equalsIgnoreCase(ipAddresses)) {
      // Proxy-Client-IP：apache 服务代理
      ipAddresses = request.getHeader("Proxy-Client-IP");
    }
    if (ipAddresses == null
        || ipAddresses.length() == 0
        || "unknown".equalsIgnoreCase(ipAddresses)) {
      // WL-Proxy-Client-IP：weblogic 服务代理
      ipAddresses = request.getHeader("WL-Proxy-Client-IP");
    }
    if (ipAddresses == null
        || ipAddresses.length() == 0
        || "unknown".equalsIgnoreCase(ipAddresses)) {
      // HTTP_CLIENT_IP：有些代理服务器
      ipAddresses = request.getHeader("HTTP_CLIENT_IP");
    }
    if (ipAddresses == null
        || ipAddresses.length() == 0
        || "unknown".equalsIgnoreCase(ipAddresses)) {
      // X-Real-IP：nginx服务代理
      ipAddresses = request.getHeader("X-Real-IP");
    }

    // 有些网络通过多层代理，那么获取到的ip就会有多个，一般都是通过逗号（,）分割开来，并且第一个ip为客户端的真实IP
    if (ipAddresses != null && ipAddresses.length() != 0) {
      ip = ipAddresses.split(",")[0];
    }

    // 还是不能获取到，最后再通过request.getRemoteAddr();获取
    if (ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ipAddresses)) {
      ip = request.getRemoteAddr();
    }
    return ip.equals("0:0:0:0:0:0:0:1") ? "127.0.0.1" : ip;
  }

  public static boolean internalIp(String ip) {
    byte[] addr = textToNumericFormatV4(ip);
    return internalIp(addr) || "127.0.0.1".equals(ip);
  }

  private static boolean internalIp(byte[] addr) {
    if (addr == null || addr.length < 2) {
      return true;
    }
    final byte b0 = addr[0];
    final byte b1 = addr[1];
    // 10.x.x.x/8
    final byte SECTION_1 = 0x0A;
    // 172.16.x.x/12
    final byte SECTION_2 = (byte) 0xAC;
    final byte SECTION_3 = (byte) 0x10;
    final byte SECTION_4 = (byte) 0x1F;
    // 192.168.x.x/16
    final byte SECTION_5 = (byte) 0xC0;
    final byte SECTION_6 = (byte) 0xA8;
    switch (b0) {
      case SECTION_1:
        return true;
      case SECTION_2:
        if (b1 >= SECTION_3 && b1 <= SECTION_4) {
          return true;
        }
      case SECTION_5:
        switch (b1) {
          case SECTION_6:
            return true;
        }
      default:
        return false;
    }
  }

  /**
   * 将IPv4地址转换成字节
   *
   * @param text IPv4地址
   * @return byte 字节
   */
  public static byte[] textToNumericFormatV4(String text) {
    if (text.length() == 0) {
      return null;
    }

    byte[] bytes = new byte[4];
    String[] elements = text.split("\\.", -1);
    try {
      long l;
      int i;
      switch (elements.length) {
        case 1:
          l = Long.parseLong(elements[0]);
          if ((l < 0L) || (l > 4294967295L)) {
            return null;
          }
          bytes[0] = (byte) (int) (l >> 24 & 0xFF);
          bytes[1] = (byte) (int) ((l & 0xFFFFFF) >> 16 & 0xFF);
          bytes[2] = (byte) (int) ((l & 0xFFFF) >> 8 & 0xFF);
          bytes[3] = (byte) (int) (l & 0xFF);
          break;
        case 2:
          l = Integer.parseInt(elements[0]);
          if ((l < 0L) || (l > 255L)) {
            return null;
          }
          bytes[0] = (byte) (int) (l & 0xFF);
          l = Integer.parseInt(elements[1]);
          if ((l < 0L) || (l > 16777215L)) {
            return null;
          }
          bytes[1] = (byte) (int) (l >> 16 & 0xFF);
          bytes[2] = (byte) (int) ((l & 0xFFFF) >> 8 & 0xFF);
          bytes[3] = (byte) (int) (l & 0xFF);
          break;
        case 3:
          for (i = 0; i < 2; ++i) {
            l = Integer.parseInt(elements[i]);
            if ((l < 0L) || (l > 255L)) {
              return null;
            }
            bytes[i] = (byte) (int) (l & 0xFF);
          }
          l = Integer.parseInt(elements[2]);
          if ((l < 0L) || (l > 65535L)) {
            return null;
          }
          bytes[2] = (byte) (int) (l >> 8 & 0xFF);
          bytes[3] = (byte) (int) (l & 0xFF);
          break;
        case 4:
          for (i = 0; i < 4; ++i) {
            l = Integer.parseInt(elements[i]);
            if ((l < 0L) || (l > 255L)) {
              return null;
            }
            bytes[i] = (byte) (int) (l & 0xFF);
          }
          break;
        default:
          return null;
      }
    } catch (NumberFormatException e) {
      return null;
    }
    return bytes;
  }

  public static String getHostIp() {
    try {
      return InetAddress.getLocalHost().getHostAddress();
    } catch (UnknownHostException e) {
    }
    return "127.0.0.1";
  }

  public static String getHostName() {
    try {
      return InetAddress.getLocalHost().getHostName();
    } catch (UnknownHostException e) {
    }
    return "未知";
  }
}
